<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>vw和vh</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        div{
            width: 100vw;
            height: 100vh;
            background: yellow;
        }
    </style>
</head>
<body>
    <!--
    100vh = 视口高度
    100vw = 视口宽度
    -->
    <div></div>
</body>
</html>